[PATCH] Bug 20662: checking whether x86_64-pc-linux-gnu-gcc implicitly enables -fstack-protector no (32bit gcc 6.2.0 pie and ssp enable)

[Magnus Granberg <zorry at gentoo dot org>]

When glibc get compile with gcc 6.2 that have been configured with
 --enable-default-pie and --enable-default-ssp. The check that check if the 
compiler use -fstack-protector as default fail on the 32bit part.

checking for libgd... no
checking for _FORTIFY_SOURCE predefine... yes
checking whether x86_64-pc-linux-gnu-gcc -m32 -Wl,-O1 -Wl,--as-needed 
implicitly enables -fstack-protector... no
checking whether the linker provides working __ehdr_start... yes

This patch make so we look for __stack_chk_fail_local in the check.
Tested on x86_64 multilib Gentoo

Changelog:

2016-10-20  Magnus Granberg  <zorry@gentoo.org>
		Denis Kaganovich  <mahatma@eu.by>

		* configure.ac:
		Add check for __stack_chk_fail_local in libc_cv_predef_stack_protector 	
		check.
		* configure: Regenerated.

---

diff --git a/configure.ac b/configure.ac
index a64aeb9..de42b6b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1667,12 +1668,14 @@ echo >&AS_MESSAGE_LOG_FD "libc_undefs='$libc_undefs'"
 # symbols (resolved by the linker), so filter out unknown symbols.
 # This will fail to produce the correct result if the compiler
 # defaults to -fstack-protector but this produces an undefined symbol
-# other than __stack_chk_fail.  However, compilers like that have not
-# been encountered in practice.
-libc_undefs=`echo "$libc_undefs" | egrep '^(foobar|__stack_chk_fail)$'`
+# other than __stack_chk_fail or __stack_chk_fail_local. However,
+# compilers like that have not been encountered in practice.
+libc_undefs=`echo "$libc_undefs" | \
+  egrep '^(foobar|__stack_chk_fail|__stack_chk_fail_local)$'`
 case "$libc_undefs" in
 foobar) libc_cv_predef_stack_protector=no ;;
 '__stack_chk_fail
+foobar'|'__stack_chk_fail_local
 foobar') libc_cv_predef_stack_protector=yes ;;
 *) AC_MSG_ERROR([unexpected symbols in test: $libc_undefs]) ;;
 esac],